Froedtert Hospital, Milwaukee, Wisconsin

Location:  Milwaukee, Wisconsin
Owner/Operator: Froedtert Hospital & Medical College of Wisconsin
Client: Shiner + Associates
Architect: Cannon Design

Vibration Mitigation for Advanced Imaging System in a High-Performance Hospital Environment

Froedtert Hospital is a premier academic medical center and the primary adult teaching affiliate of the Medical College of Wisconsin. Situated on the Milwaukee Regional Medical Center campus, it serves as a major referral hub for advanced medical care across the Midwest. With 776 beds and the region’s only adult Level I Trauma Center, Froedtert delivers comprehensive emergency and specialty services while maintaining a reputation for excellence in patient care.

As part of a five-year master plan, Froedtert Hospital and the Medical College of Wisconsin envisioned a transformative approach to surgical and interventional care. The plan centered on the creation of the Integrated Procedural Platform (IPP) —a single, centrally located floor designed to consolidate services previously spread across four separate hospital locations. This innovative platform would accommodate advanced surgical technologies, streamline workflows, and enhance patient safety and efficiency. The new operating rooms replaced outdated basement facilities from the 1970s and were positioned adjacent to magnetic resonance imaging suites, enabling real-time intraoperative scanning and reducing delays in critical procedures.

Vibration Assessment Challenges for GE iMRI Installation

The installation of a GE iMRI system within the IPP introduced a unique engineering challenge. This highly sensitive imaging device, weighing approximately 17,000 pounds, has stringent limits on floor vibration to ensure imaging accuracy. The proposed location on Level 3 of the building featured a steel-framed composite concrete floor surrounded by active hospital corridors, elevators, and mechanical systems—all potential sources of vibration. Maintaining compliance with GE Healthcare’s strict criteria was essential, particularly in an environment where pedestrian and gurney traffic would be frequent.

Comprehensive Vibration Analysis and Measurement Approach

HGC Noise Vibration Acoustics was contracted to undertake a detailed vibration assessment combining on-site measurements with advanced dynamic finite element modeling. The team began by reviewing the IPP’s architectural and structural drawings to understand the floor system supporting the MRI system. Measurements were conducted using calibrated seismic accelerometers in accordance with GE Healthcare’s MR Site Vibration Test Guidelines, capturing both steady-state vibrations from mechanical systems and transient vibrations caused by foot traffic and gurney movement. Tests were performed during periods of minimal construction activity to establish baseline conditions and during simulated pedestrian traffic to evaluate real-world scenarios.

Dynamic Finite Element Modeling for Predictive Vibration Control

To complement field measurements, HGC developed a dynamic finite element model of the IPP floor system. This model simulated the impact of the MRI system’s added mass and assessed how proposed structural reinforcements would influence vibration response. Predictive modeling allowed the team to evaluate the effectiveness of upgrades and forecast vibration performance under operational conditions.

Key Findings from Vibration Assessment and Analysis

The assessment revealed that ambient vibration levels at the proposed iMRI location generally met GE Healthcare’s steady-state criteria, except during minor construction activity when temporary equipment introduced elevated levels. Transient vibrations from routine heavy footfalls and gurney passages occasionally exceeded GE’s limits, but these peaks occurred at higher frequencies and did not align with the floor’s dominant resonant frequency. Finite element modeling confirmed that the addition of the iMRI’s mass would lower the resonant frequency of the floor bay; however, planned structural upgrades would restore it to its original value. Simulations predicted that, with these upgrades in place, transient vibration levels would remain within acceptable limits for the iMRI’s operation.

Consulting Recommendations for Vibration Mitigation and Compliance

Through precise measurement and predictive modeling, HGC provided Froedtert Hospital and Cannon Design with actionable recommendations to ensure the successful installation of the GE iMRI system. These included implementing structural reinforcements prior to installation and conducting post-construction vibration surveys to verify compliance. By proactively addressing vibration risks, HGC helped safeguard the performance of critical imaging equipment and supported Froedtert Hospital’s commitment to excellence in surgical outcomes.

Collaborative Consulting for Complex Healthcare Projects

HGC’s involvement extended beyond technical analysis to include consultation with project stakeholders and equipment manufacturers, ensuring alignment between design objectives and operational requirements. This collaborative approach enabled Froedtert Hospital to achieve its vision for a state-of-the-art Integrated Procedural Platform while maintaining uninterrupted surgical operations throughout a complex, multi-year renovation.

Vibration Consulting Services Provided by HGC Noise Vibration Acoustics

• Review of architectural and structural drawings

• On-site vibration measurements and analysis

• Dynamic finite element modeling of floor systems

• Assessment of ambient and transient vibration sources

• Recommendations for structural upgrades and vibration mitigation

• Consultation with project stakeholders and equipment manufacturers

• Post-construction vibration survey planning